MXS-1220: Add /maxscale/tasks resource

The resource shows all active tasks inside MaxScale.

include/maxscale/housekeeper.h

@@ -68,9 +68,61 @@ extern void hkshutdown();
  */
 extern void hkfinish();
 
-extern int  hktask_add(const char *name, void (*task)(void *), void *data, int frequency);
-extern int  hktask_oneshot(const char *name, void (*task)(void *), void *data, int when);
-extern int  hktask_remove(const char *name);
-extern void hkshow_tasks(DCB *pdcb);
+/**
+ * @brief Add a new task
+ *
+ * The task will be first run @c frequency seconds after this call is
+ * made and will the be executed repeatedly every frequency seconds
+ * until the task is removed.
+ *
+ * Task names must be unique.
+ *
+ * @param name      Task name
+ * @param task      Function to execute
+ * @param data      Data passed to function as the parameter
+ * @param frequency Frequency of execution
+ *
+ * @return 1 if task was added
+ */
+int hktask_add(const char *name, void (*task)(void *) , void *data, int frequency);
+
+/**
+ * @brief Add oneshot task
+ *
+ * The task will only execute once.
+ *
+ * @param name Task name
+ * @param task Function to execute
+ * @param data Data passed to function as the parameter
+ * @param when Number of seconds to wait until task is executed
+ *
+ * @return 1 if task was added
+ */
+int hktask_oneshot(const char *name, void (*task)(void *) , void *data, int when);
+
+/**
+ * @brief Remove a task
+ *
+ * @param name Task name
+ *
+ * @return 1 if the task was removed
+ */
+int hktask_remove(const char *name);
+
+/**
+ * @brief Show the tasks that are scheduled for the house keeper
+ *
+ * @param pdcb The DCB to send to output
+ */
+void hkshow_tasks(DCB *pdcb);
+
+/**
+ * @brief Show tasks as JSON resource
+ *
+ * @param host Hostname of this server
+ *
+ * @return Collection of JSON formatted task resources
+ */
+json_t* hk_tasks_json(const char* host);
 
 MXS_END_DECLS